The thing that sparked the idea was a badly disclosed sponsorship. The saving time bits are great, and that's why there's more features now than just ads, you can skip intros too. However, I did start this explicitly due to being frustrated with the state of deception in the sponsorship world, and that remains my main motivation.
That may have been the initial motivation, but SponsorBlock isn't a tool to reveal hidden product placement or sponsorships. It's not described that way on your site or the add-on pages, used that way, or - if we're honest - popular for that reason.
In the end, the motivation is not the tool as implemented.
The thing that sparked the idea was a badly disclosed sponsorship. The saving time bits are great, and that's why there's more features now than just ads, you can skip intros too. However, I did start this explicitly due to being frustrated with the state of deception in the sponsorship world, and that remains my main motivation.